Method of manufacturing footwear with thermal retention layer

ABSTRACT

A boot that includes a rubber sole, and an upper portion attached to the rubber sole. The upper portion is made from rubber. The rubber sole includes a layer of aerogel material for an interior section of the boot. The layer of aerogel material covers the interior portion of the rubber sole along with a front part of the boot such that the layer of aerogel material contacts a sole of a foot of a wearer while also surrounding the toes of the wearer. In certain embodiments, the layer of aerogel material has a thickness ranging from 0.1 millimeters to 20 millimeters.

FIELD OF THE INVENTION

This invention generally relates to a method of manufacturing footwear with a thermal retention layer.

BACKGROUND OF THE INVENTION

Conventional cold-weather footwear often incorporates traditional insulating materials, such as goose down, stiff insulating foam or synthetic fibers, to reduce the loss of heat from the wearer's foot. While these insulating materials attempt to minimize the heat loss from the wearer's foot, they suffer from the shortcomings (i.e., expensive, bulky, heavy) making transport and storage of the footwear somewhat difficult.

Embodiments of the invention represent an advancement over the state of the art with respect to the manufacture of cold-weather footwear. These and other advantages of the invention, as well as additional inventive features, will be apparent from the description of the invention provided herein.

BRIEF SUMMARY OF THE INVENTION

In one aspect, embodiments of the invention provide a method of manufacturing footwear having a sole and an upper attached to the sole. The method includes the steps of cementing a front portion of the sole to a corresponding front portion of the upper, and goodyear welting a rear portion of the sole to a corresponding rear portion of the upper. The goodyear welting is performed along at least half the length of the sole, and the cementing is performed along at least 40 percent of the length of the sole.

In a particular embodiment, the percentage of the length of the sole that is attached to the upper via cementing ranges from 40 percent to 50 percent. In another embodiment, the percentage of the length of the sole that is attached to the upper via goodyear welting ranges from 50 percent to 60 percent. In yet another embodiment, the percentage of the length of the sole that is attached to the upper via goodyear welting is 55 percent, and the percentage of the length of the sole that is attached to the upper via cementing is 55 percent.

Embodiments of the method further include assembling an insole to the rubber sole and attaching a rib to the insole. The rib may be made from ethylene vinyl acetate. In certain embodiments, the method calls for attaching a welt to the upper and to the rib. The welt may be from one of leather, linen, and a synthetic material. Attaching the welt to the upper and to the rib may include using a lock stitch to attach the welt to the upper and to the rib. Furthermore, goodyear welting a rear portion of the sole may call for filling a cavity enclosed by the welt with a filling material.

In some embodiments, the filling material is made from a porous material. In a further embodiment, cementing a front portion of the sole calls for cementing a front portion of the sole using a high-strength adhesive or hide glue.

Other aspects, objectives and advantages of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings incorporated in and forming a part of the specification illustrate several aspects of the present invention and, together with the description, serve to explain the principles of the invention. In the drawings:

FIG. 1 is a side view of a footwear item, constructed in accordance with an embodiment of the invention;

FIG. 2 is a partial cross-section of the footwear item of FIG. 1;

FIG. 3 is a top view of the footwear item of FIG. 1;

FIG. 4 is a fully cross-sectional view of the footwear item of FIG. 1;

FIG. 5 is a perspective view of an aerogel thermal retention layer incorporated into the footwear item of FIG. 1, according to an embodiment of the invention;

FIG. 6 is another perspective view of the aerogel thermal retention layer of FIG. 5;

FIG. 7 is a cross-sectional view of the aerogel thermal retention layer of FIG. 5

FIG. 8 is a schematic illustration showing various aspects of the goodyear welting process, in accordance with an embodiment of the invention;

FIG. 9 is an illustration showing side, top, and partial cross-sectional views of the footwear item showing various aspects of the goodyear welting and cementing processes, in accordance with an embodiment of the invention; and

FIG. 10 is a side view and partial cross-section of the footwear item showing various aspects of the goodyear welting and cementing processes, in accordance with an embodiment of the invention.

While the invention will be described in connection with certain preferred embodiments, there is no intent to limit it to those embodiments. On the contrary, the intent is to cover all alternatives, modifications and equivalents as included within the spirit and scope of the invention as defined by the appended claims.

DETAILED DESCRIPTION OF THE INVENTION

An embodiment of the present invention is illustrated in FIGS. 1-4 as a series of plan, perspective, and cross-sectional views of a footwear item 100, constructed in accordance with an embodiment of the invention. As will be explained below, the footwear item 100 of the present invention includes a thermal retention layer 110 to provide a wearer increased protection against the cold.

The footwear item 100 has a rubber sole 102 attached to an upper 104 that is also made from rubber. In particular embodiments, the upper 104 is made from a combination of vulcanized rubber and neoprene rubber. In the embodiment of FIG. 4, the interior of the upper 104 includes an attached layer 106 lining the interior of the footwear item 100. This attached layer 106 may be a breathable air mesh lining. In certain embodiments, the attached layer 106 is made from nylon. As can also be seen in the embodiment of FIG. 4, there is a layer of thermal insulation 108 sandwiched between the attached layer 106 and the upper 104. In some embodiments, the thermal insulation 108 is a synthetic insulating material with insulating properties superior to that of most natural materials.

Still referring to FIG. 4, the rubber sole 102 has the thermal retention layer 110 disposed on the interior part of the rubber sole 102. The thermal retention layer 110 may be made from an aerogel material. Aerogels are synthetic, porous, ultralight materials derived from a gel, in which the liquid component for the gel has been replaced with a gas. Aerogels have a porous solid network that contains air pockets, with the air pockets taking up the majority of space within the material. Typically, aerogels are about 99.8% air. The result is a solid with extremely low density and extremely low thermal conductivity. Aerogels can be made from a variety of chemical compounds.

Despite the name, aerogels are solid, rigid, and dry materials that do not resemble a gel in their physical properties. While aerogels tend to be somewhat friable, they also tend to be very strong structurally. Their unusually high load-bearing abilities are due to their dendritic microstructure, in which spherical particles, with an average size of 2-5 nanometers are fused together into clusters. Due to being composed of mostly air, aerogels are good thermal insulators because air is a poor conductor of heat. Furthermore, because their microstructure prevents net gas movement, aerogels do not transfer heat by convection.

In the embodiment shown, the thermal retention layer 110 is designed to cover substantially the entire interior part of the rubber sole 102 so that the thermal retention layer 110 is in contact with the entire sole of the wearer's foot. In a particular embodiment, the thermal retention layer 110 is a layer of aerogel material with a thickness ranging 0.1 millimeters to 20 millimeters.

In the embodiment shown, the front section of the rubber sole 102 has a toe cap 112 in which the rubber extends up, over, and around the front of the footwear item 100 so as to protect the toes of the wearer. In a further embodiment, the rear section of the rubber sole 102 has a heel counter 114 that extends up along the rear part of the footwear item 100 so as to protect the heel of the wearer.

FIGS. 5-7 provide various perspective and cross-sectional views of the thermal retention layer 110. At the front of the thermal retention layer 110, the material extends up and around to cover the toes of a wearer. As used in this application, “front” refers to the part of the footwear item 100 that protects the toes of the wearer, and “rear” refers to the part of the footwear item 100 that protects the heel of the wearer. When fabricated as shown in FIGS. 5-7 the thermal retention layer 110 can be installed much like at insert into the footwear item 100 after its manufacture.

Referring again to FIG. 4, embodiments of the footwear item 100 include a removable footbed 116 which is disposed on top of the thermal retention layer 110. Like the thermal retention layer 110, the removable footbed 116 may be designed as an insert to be installed after manufacture of the footwear item 100.

The footwear item 100 can be manufactured using the process described below, in accordance with an embodiment of the invention. FIGS. 8-11 illustrate embodiments of a manufacturing method for footwear that includes goodyear welting and cementing. These two methods will be described in more detail below.

FIGS. 8-10 are schematic illustrations showing various aspects of the goodyear welting process, while FIGS. 9 and 10 illustrate the cementing process. The goodyear welt construction” involves stitching a welt 120 to the upper 104 and a strip of pre-formed canvas, ethylene vinyl acetate (EVA), or polyvinyl chloride (PVC) (shown in FIGS. 9 and 10) which constitutes a rib 130 that runs all around and bottom (known as “gemming”) attached to the insole 124 of the footwear item 100 as an attachment-point for the rubber sole 102 (depending on the goodyear welt variant). The cavity or space enclosed by the welt 120 is typically filled with a filling material 126, such as cork or some other suitable filler material (usually either porous or perforated, for breathability), and the rubber sole 102 is then stitched to the welt 120. In some embodiments, a high-strength adhesive, like contact cement or hide glue, may be used in combination with the welt stitching 122. While goodyear welting is generally more expensive and time-consuming than cementing, the extra layers involved provide more support and greater water resistance.

In a particular embodiment, the first part of the process is preparing the insole 124 for stitching. This is done by creating the perpendicular rib 130 that runs across the insole 124. The second step is to “last” the footwear item 100. A “last” is a mechanical form in the shape of a foot. Lasting is done by stretching the rubber sole 102 over the last and attaching it, along with the insole 124, to the last. The third step is the actual welting. The upper 104 is shaped over the last and fastened on by sewing the welt 120, which, in specific embodiments, may be a leather, linen or synthetic strip of material, to the insole 124 and upper 104. In certain instances, a shoe-specific thread is sewn through the welt 120, the upper 104, and the insole rib 130. Through a separate stitch 128, the welt 120 is attached to the rubber sole 102. For both of these stitching points, a lockstitch may be used so that the chain of stitches 122, 128 will not unravel if any stitch breaks down at any particular point on the footwear item 100.

Compared to goodyear welting, cementing is a relatively less expensive, faster, and more common method for attaching the upper 104 and rubber sole 102 for the footwear item 100. As applied to the footwear item 100 of the present invention, with cementing, once the upper 104 is shaped and completed around the last, the rubber sole 102 is attached with an adhesive and no welting is needed. Cementing is especially advantageous when used as a method of attachment for resilient, or rubbery soles of the type used in footwear item 100.

In conventional footwear whose manufacture incorporates both goodyear welting and cementing processes, the cementing is done on the rear portion of the footwear while the goodyear welting is done on the front portion. In the footwear item 100 disclosed herein and as can be seen in FIG. 10, the cementing is done on the front portion of the footwear while the goodyear welting is done on the rear portion. The process as described herein has several advantages which include, but are not limited to ease of manufacturing, reduced cost of manufacturing, increased durability, and improved comfort.

In various embodiments of the invention, such as can be seen in FIG. 10, the portion of the footwear item 100 which is manufactured using goodyear welting represents a percentage of the total length of the sole of the footwear item 100 starting at the rear end of the footwear item 100 and extending toward its center. Similarly, the portion of the footwear item 100 which is manufactured using cementing represents a percentage of the total length of the sole of the footwear item 100 starting at the front end of the footwear item 100 and extending toward its center. In a particular embodiment, the percentage of the length of the sole that is attached to the upper via cementing ranges from 40 percent to 50 percent. In another embodiment, the percentage of the length of the sole that is attached to the upper via goodyear welting ranges from 50 percent to 60 percent. In yet another more particular embodiment, the percentage of the length of the sole that is attached to the upper via goodyear welting is 55 percent, and the percentage of the length of the sole that is attached to the upper via cementing is 55 percent.

All references, including publications, patent applications, and patents cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein.

The use of the terms “a” and “an” and “the” and similar referents in the context of describing the invention (especially in the context of the following claims) is to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms “comprising,” “having,” “including,” and “containing” are to be construed as open-ended terms (i.e., meaning “including, but not limited to,”) unless otherwise noted. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.

Preferred embodiments of this invention are described herein, including the best mode known to the inventors for carrying out the invention. Variations of those preferred embodiments may become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventors expect skilled artisans to employ such variations as appropriate, and the inventors intend for the invention to be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context. 

What is claimed is:
 1. A method of manufacturing footwear having a sole and an upper attached to the sole, the method comprising the steps of: cementing a front portion of the sole to a corresponding front portion of the upper; and goodyear welting a rear portion of the sole to a corresponding rear portion of the upper; wherein the goodyear welting is performed along at least half the length of the sole, and the cementing is performed along at least 40 percent of the length of the sole.
 2. The method of claim 1, wherein the percentage of the length of the sole that is attached to the upper via cementing ranges from 40 percent to 50 percent.
 3. The method of claim 1, wherein the percentage of the length of the sole that is attached to the upper via goodyear welting ranges from 50 percent to 60 percent.
 4. The method of claim 1, wherein the percentage of the length of the sole that is attached to the upper via goodyear welting is 55 percent, and the percentage of the length of the sole that is attached to the upper via cementing is 55 percent.
 5. The method of claim 1, wherein goodyear welting a rear portion of the sole comprises assembling an insole to the rubber sole and attaching a rib to the insole.
 6. The method of claim 5, wherein the rib is made from ethylene vinyl acetate.
 7. The method of claim 5, wherein goodyear welting a rear portion of the sole comprises attaching a welt to the upper and to the rib.
 8. The method of claim 7, wherein the welt is made from one of leather, linen, and a synthetic material.
 9. The method of claim 7, wherein attaching the welt to the upper and to the rib comprises using a lock stitch to attach the welt to the upper and to the rib.
 10. The method of claim 1, wherein goodyear welting a rear portion of the sole comprises filling a cavity enclosed by the welt with a filling material.
 11. The method of claim 10, wherein the filling material is made from a porous material.
 12. The method of claim 1, wherein cementing a front portion of the sole comprises cementing a front portion of the sole using a high-strength adhesive or hide glue. 